This paper is one of a family of four papers (see References) describing different aspects of the design and implementation of a financial settlement system. The system was developed to replace an existing legacy system. Designed to be both flexible and high performance, the system was developed over a period of three years using a component-based approach and object-oriented techniques. The system comprised over 1,000,000 lines of C++ source code (of which 75% was machine generated), divided into 1,500 classes spread over 30 component systems.

In this paper, examples of components from the settlement domain are discussed with reference to wider architectural issues such as layering, interfaces, and dependency management. The process by which a component-based system may be designed and the implications for team working are also discussed, as are issues of designing components for reuse.